Update to new naming standards
Update to new naming standards

dob -> born_on

ga-wdi-boston/rails-activerecord-crud-diagnostic,ga-wdi-boston/rails-crud-assessment,ga-wdi-boston/rails-crud-diagnostic,ga-wdi-boston/rails-crud-solo-assessment,ga-wdi-boston/rails-crud-diagnostic,ga-wdi-boston/rails-crud-solo-assessment,ga-wdi-boston/rails-activerecord-crud-diagnostic,ga-wdi-boston/rails-crud-assessment